Backwards Water Slide

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Backwards Water Slide

Have you ever slid down a water slide? It’s a slide with water running down it so you can slide really fast. Well, here’s your chance to ride UP the slide. The “Flow Rider” pumps water up a slippery hill at high speed, while swimmers fling themselves onto it on surfboards. Some people swim on their bellies, but the brave ones stand on their boards to surf. The water is so strong that some kids were flung up to the top of the slide and right over the edge! How much water does it take to make a wave like this — and how long can you ride it without wiping out?

Wee ones: On which side of that photo is someone already sliding, the left or the right?

Little kids: Only 1 kid at a time can ride on one side. If 4 extra people join in, how many riders would that side have? Bonus: If 2 of those were surfing instead of bellyboarding, how many would be bellyboarding?

Big kids: If 8 people are in line in front of you and a new person starts every 5 minutes, how long do you have to wait for your turn? Bonus: If you try to stand on your surfboard every 3rd ride starting with the 3rd, will you surf on your 42nd turn?

The sky’s the limit: We’re told that it costs about $500,000 to build a Flow Rider. How does that relate to a million dollars? And how many of these could a hotel chain build for $10 million?

Answers:Wee ones: On the right.

Little kids: 5 riders. Bonus: 3 bellyboarders.

Big kids: 40 minutes. Bonus: Yes! 42 is a multiple of 3. You can tell because its digits add up to a multiple of 3 themselves: 4 + 2 = 6.

The sky’s the limit: $500,000 is half a million, so for $1 million they can build 2 Flow Riders. That means $10 million can build 20 of them.

About the Author

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.